Minimum action screw torque

[Blackie Lawless]

What is considered the minimum action screw torque?

Lot’s of info on torque values but I haven’t come across this perspective yet.

My current setup is a 700 SA B&C M40, factory BDL bottom metal, and it’s a .308

I read an article pointing out 40in/lbs = 800 pounds of force(tension/compression)

So that is 100lbs of tension/compression for every 50in/lbs

 

[Hkmiller]

What is considered the minimum action screw torque?

Lot’s of info on torque values but I haven’t come across this perspective yet.

My current setup is a 700 SA B&C M40, factory BDL bottom metal, and it’s a .308

I read an article pointing out 40in/lbs = 800 pounds of force(tension/compression)

So that is 100lbs of tension/compression for every 50in/lbs

My gunsmith said on those Remington 700 Factory actions he likes 45 inch pounds on the back screw and 65 on the front

 

[Supersubes]

Certainly there’s a max torque for the receiver and screws, but whats between the screw head and the receiver is more important. A properly bedded stock with pillars, vs a chassis, vs a piece of walnut. There isnt one number for minimum. Assuming your receiver fits the b&c inlet well, just tight enough to not shoot loose would work, but you’ll have to test it.

 

[Mike Casselton]

1/4×28 screws normally use 50-70 in-lbs of torque for metal to metal situations.
This is based on the threads being clean and dry.
If any lubrication is involved I would use the minimum torque rating.

As pointed out above, I also tend to use 65 Front & 40-Rear for pillars or metal chassis.

For a wood stock I'd use 40 or maybe less if it doesn't have pillars.

 

[Blackie Lawless]

Certainly there’s a max torque for the receiver and screws, but whats between the screw head and the receiver is more important. A properly bedded stock with pillars, vs a chassis, vs a piece of walnut. There isnt one number for minimum. Assuming your receiver fits the b&c inlet well, just tight enough to not shoot loose would work, but you’ll have to test it.

This is exactly what I was thinking

 

[Blackie Lawless]

1/4×28 screws normally use 50-70 in-lbs of torque for metal to metal situations.
This is based on the threads being clean and dry.
If any lubrication is involved I would use the minimum torque rating.

As pointed out above, I also tend to use 65 Front & 40-Rear for pillars or metal chassis.

For a wood stock I'd use 40 or maybe less if it doesn't have pillars.

I have seen it suggested that the Remington factory BDL bottom metal should not be torque above 35 per Remington

Obviously bedding I think is the best option, but there probably should be a sweet spot whether it is bedded or not

My guess would be hand tight with a driver and possibly 5-10in/lbs more

And presumably 1in/lb increments could probably find the most precise point

 

[Mike Casselton]

Nothing wrong with 35 inlb on the BDL.




Do you have a torque wrench that is calibrated less than +/- 1in-lb increments?
I doubt you can actually find one that's affordable.

5 in-lb increments would be easier to accomplish.


How do you know it's the torque value changing accuracy?

Are you shooting indoors?

Shooting outdoors over properly read wind flags?

Are you capable of shooting with the consistency to determine torque value changes?

You mention the Remington BDL.

Is the rifle and ammo capable of giving you the accuracy to even bother with this test?

 

[Blackie Lawless]

Yes I have a wrench that runs 20-100 in/lbs in 1 in/lb increments. They are pretty common

I can shoot consistently enough

I actually tested it today as much as possible with the time allowed.

The results are pretty obvious actually and I ran a few last week also.

I saw best results so far at 55 front/55 rear and the best group today at 65 front/45 rear. I think the 65/45 group is probably better, and these are 175gr SMK’s

This rifle doesn’t like Lake City M80 147’s at all

 

[Blackie Lawless]

My gunsmith said on those Remington 700 Factory actions he likes 45 inch pounds on the back screw and 65 on the front

I tried 65/45 today and got the best group of the test today using it

Thank you!

 

[Holliday]

I run 53 lbs on my Magpul Hunter stocks…..

 

[huntnh]

I run the 65 45 on all of my center fires on my rim fires I’m getting the best groups at 40 inch lbs

 

[pmclaine]

Yes I have a wrench that runs 20-100 in/lbs in 1 in/lb increments. They are pretty common

I can shoot consistently enough

I actually tested it today as much as possible with the time allowed.

The results are pretty obvious actually and I ran a few last week also.

I saw best results so far at 55 front/55 rear and the best group today at 65 front/45 rear. I think the 65/45 group is probably better, and these are 175gr SMK’s

This rifle doesn’t like Lake City M80 147’s at all

I don't think many "precision" rifles are going to shine with M80.

My experiments with torque on a pillared M40....

Torque Test - M40rifle.com

The later model M40's come from the builder with a book that states what the proper action torque is. Doesnt mean its right but at least there is a deffinitive

www.m40rifle.com

 

[Blackie Lawless]

I don't think many "precision" rifles are going to shine with M80.

My experiments with torque on a pillared M40....

Torque Test - M40rifle.com

The later model M40's come from the builder with a book that states what the proper action torque is. Doesnt mean its right but at least there is a deffinitive

www.m40rifle.com

I suspected it would shoot better in a 1/12 twist, mine is 1/10 20”bbl

This rifle is a 700 tactical

 

[Blackie Lawless]

I don't think many "precision" rifles are going to shine with M80.

My experiments with torque on a pillared M40....

Torque Test - M40rifle.com

The later model M40's come from the builder with a book that states what the proper action torque is. Doesnt mean its right but at least there is a deffinitive

www.m40rifle.com

Love the write up!!!

Thank you for sharing that link!

 

[Mike Casselton]

Yes I have a wrench that runs 20-100 in/lbs in 1 in/lb increments. They are pretty common

I can shoot consistently enough

I actually tested it today as much as possible with the time allowed.

The results are pretty obvious actually and I ran a few last week also.

I saw best results so far at 55 front/55 rear and the best group today at 65 front/45 rear. I think the 65/45 group is probably better, and these are 175gr SMK’s

This rifle doesn’t like Lake City M80 147’s at all

I'm glad the 65/45 worked for you.

One thing I wanted to point out about torque wrenches though.

Like yours, mine has settings in 1lb increments.

What mine (Snap-On) doesn't have is actual calibrated accuracy that allows it to be repeatable and correct every time it's used.
In fact, nearly every torque wrench made is accurate to +/- 3% or worse.

Some (most) can't hold +/- 3-inlbs on any setting and are far worse at the extreme settings like the upper and lower 20% of its range.

One thing they do for us is to keep us solidly in the ball park if used properly.

To own a torque wrench that is capable and repeatable in 1inlb increments would be a very expensive procurement and frankly, unnecessary for what we do.